Rachio Serial Missing

Purchased Rachio 3 from Facebook seller. Sticker missing from unit and serial number on box does not match. Connected device to wifi manually but cannot link to app. Please help! Support says they cant do anything without serial. I have the mac address though and had no issues adding serial from box to my email account.

Not sure what there is to do…not sure why someone would remove a serial sticker from a unit unless it was stolen. Did support say that they could do anything with a MAC address?

Unfortunately, they said they needed a serial… hoping someone has a work around… Really bummed here…

Is the theft of rachio devices really a thing? Kind of strange they would still use a box with a legitimate serial…